Stamping apparatus



l 9 v. A. POLLECK ET AL 2,902,924

STAMPING APPARATUS Filed Feb. 18, 1957 3 Sheets-Sheet 2 /N [/5 N TORS ATTORNEYS.

p 8, 1959 v. A. POLLECK ET AL 2,902,924

STAMPING APPARATUS Filed Feb. 18, 1957 3 Sheets-Shet 3 v i I 7mm%/&A WZWW B) W 9 7W ATTORNEYS.

United Staes STAMPING APPARATUS Application February 18, 1957', Serial No. 640,724

13 Claims. (Cl. -1-8) This invention relates to stamping apparatus and more particularly to apparatus for hot stamping numerals or insignia on the conical surfaces of plastic knobs and the like.

Heretofore, it has been the usualpractice in hot stamping knobs and the like to mount the knob on a rotatable shaft and to pass an elongated straight die over the surface of the knob with a pigmented tape therebetween to. impress the desired insignia into the knob surface and to deposit colored pigment from the tape in the impressions. In this process the conical angle of the knob surface is limited since a large angle creates appreciable differences in the lengths. of travel of the small and large ends of the conical surface and causes slipping and smearing. Furthermore, the apparatus required for such operations is relatively large and cumbersome and is slow in operation.

It is one of the objects of the present invention to provide a stamping apparatus in which conical knobs and the like of substantially any desired cone angle can be stamped ,without slippingor smearing.

Another object is to provide stamping apparatus in which av rotatable conical. die engages the conical. surface of the knob and rotates synchronously therewith to. effect stamping. with no slipping or smearing.

According to afeature of the invention, the. die and knob are mounted on shafts lying in a common plane at an angle to each other equal to the conical angle of the knob and the shafts are moved relatively to and from each other to bring the conical surfaces of the knob and die into engagement for a stamping operation and to separate. the knob, and; die from, each other at the end of the stamping operation for removal of the completed knob. and mounting of a new knob. tov bestamped.

Still another object is to provide stamping apparatus in which the knob is. held. on. a support on one of the shafts by a holder movable axially and laterally toward and from the support and an ejector is provided in. the support to eject a finished knob therefrom.

A further object, is to provide stamping: apparatus in which the operation is automatically controlled in a predetermined sequence in a complete cycle to provide a semi-automatic type of operation.

A still further object is to provide stamping apparatus in which the shafts carrying the die and knob are driven by longitudinally movable racks through driving gears on the shafts, and the racks are slidably connected to. a driving motor to accommodate movement of the shafts toward and away from each other.

According to a feature of the invention, the shafts are mounted for angular adjustment to accommodate different conical angles of knobs and for lateral shifting relative to the direction of their movement toward and away from each other to maintain them in proper position relative to the racks.

Yet another object is to provide stamping apparatus in which a tape is fed between the conical surfaces of the atent 2,902,924 Patented Sept. 8, 1959 die and knobby friction driven feeding means driven by the drive motor for the shafts.

According to a feature of the invention, a ratchet is provided in the feeding means to. prevent reverse movement thereof and thereby to prevent back-ing up of the tape.

Still another object is toprovide stamping apparatus in which the die is heated by internal heating means and the shaft on which the die is mounted extends through a hollow bearing block through which exhaust air from an air motor is passed to cool the shaft and bearings. Preferably the air carries oil to lubricate the bearings.

According to a feature of the invention, the end of the shaft carrying the. die is formed with a plurality of axially extending bores in which heating units are mounted and the die is recessed partially to receive the heating units.

The above and other objects and features of the invention will be more readily apparent from the following description when readin connection with the accompanying drawings, in which:

Figure 1 is a perspective view of a typical stamped knob on which the apparatus of the present invention is adapted to operate;

Figure 2 is, a perspective view of the stamping apparatus embodying the invention;

Figures 3 and 4 are partial side elevations with parts broken away of the knob holding device;

Figure 5 is a partial plan view showing the shafts and supports therefor which hold the knobs and the die;

Figure 6' is a perspective view with parts broken away and in section of the tape feeding means and Figure 7 is a diagrammatic view of the control circuit.

The apparatus of the present invention is adapted to hot stamp numerals or similar insignia onconical surfaces of knobs or the like, as shown. for example in Figures. l and 5. The knob, as illustrated in Figure 1, is typical of knobs used on various electrical devices such as radio or television sets and comprises a conical skirt portion 10 on which insignia, as shown at 11, is impressed. The knob provides a cylindrical projecting finger portion 12 which may be formed with ribs 13, or the like, to be grasped by the fingers so that the knob can be easily turned.

Knobs of this character are normally molded of plastic and are hollow, as best seen in section in Figure 5. In a typical knob, as seen in Figure 5', the inside of the cylindrical finger portion 12 carries a hub 14 for fitting onto a shaft on the apparatus and may be formed with reinforcing fins to strengthen the knob surface and to maintain the several walls of the knob of substantially uniform thickness for proper molding.

Knobs of this character are normally molded without any. insignia on the conical skirt portion 10 and the desired insignia is later stamped into the skirt portions by a hot stamping process in which a pigmented tape is employed' so that the pigment in the tape, which is of a color contrasting to the color of the knob, will be deposited in the stamped insignia. In some cases, the insignia may be impressed into the surface of the knob and in others the stamping operation serves primarily to deposit the pigment from the tape on the knob surface without actually impressing the surface. The present apparatus may perform either type of stamping operation and is capable of stamping knobs or similar devices having a conical angle of substantially any desired value.

The. apparatus, as best seen in Figure 2, comprises a table, 15 suitably supported on legs and having an opening 16 therethrough. The topof the table carries fixed guides 17 on which a plate 18 is shiftable from front to back and fixed guides 19. extending longitudinally of the. table.

The plate 18 carries an angularly adjustable plate 21 which is rotatable about a vertical axis and which in turn carries a bearing block 22. As best seen in Figure 5, the bearing block 22 carries spaced bearings 23 in which a shaft 24 is rotatably mounted. The shaft 24 carries a driving gear 25 adjacent to one end of the bearing block 22 and at the opposite end of the bearing block may detachably carry a support 26 for the knobs. The support, as shown, includes a generally conical head shaped to fit into the inside of a knob to be stamped and having ejector pins 27 extending slidably through the head to engage the knob and force it from the support. The pins are carried by a plate 28 slidable in the support and urged in a direction to retract the pins by a spring 29. The plate 28 is adapted to fit onto the reduced end of a rod 31 extending slidably through the shaft 24 to move the plate 28 against the spring 29 for ejecting a completed knob from the support.

The guides 19 carry a slidable plate 32 for linear sliding movement along the guide and toward and away from the support 21. An angularly adjustable support 33 is mounted on the plate 32 for angular adjustment about an axis and carries a bearing block 34 in which a shaft 35 is rotatably mounted. As seen in Figure 5, the bearing block 34- carries bearings 36 adjacent its ends in which the shaft 35 is journalled and is hollow and enlarged between the bearings to leave an annular space around the shaft through which cooling air may be circulated, as described hereinafter. The shaft 35 carries a gear 37 at one end of the bearing block through which the shaft may be driven and at its opposite end is enlarged and formed with a plurality of axially extending bores 38 arranged in annular array around the axis of the shaft. The bores 38 receive electric heaters 39 which fit into the bores and project axially therefrom, as shown. The heaters 39 may be energized through wires extending through the hollow shaft 35 and connected to a source of heating current through slip rings, or the like, not shown. The heaters are controlled by a pyrometer unit 41 mounted in a central reduced bore in the shaft and projecting beyond the end of the shaft.

The shaft 35 is adapted to carry a die indicated generally at 42 which is internally recessed to receive the heaters 39 and the pyrometer unit 41. The die may be secured to the shaft by a central screw 43 extending axially through the die and which is hollow to receive the pyrometer unit, as shown. At its upper end the die is formed with a conical surface 44 having the same conical angle as the skirt portion of the knob and which is formed with numerals or other insignia to be impressed on the knob.

The shafts are adapted to be driven in reverse directions by an air motor 45 mounted on a support 46 carried by the back edge of the table and containing a reciprocable piston which is connected to a cross member 47 lying parallel to the table top to move the cross member toward and away from the table top. The driving means and 37 mesh with vertically elongated racks 48 and 49 which are carried by the cross member 47 and which mesh with the gears respectively. The racks may be supported and guided by suitable fixed guides 51 carr1ed by the supports 21 and 33 respectively to hold the racks 1n accurate meshing engagement with the gears.

To secure the racks to the cross member 47, the cross member is formed with elongated slots 52 parallel to the length of the cross member through which reduced upper end portions on the racks may slidably extend. The upper ends of the racks above the cross member carry washers 53 and nuts 54 for holding the racks against longitudinal movement relative to the cross member while permitting sliding thereof lengthwise of the cross member.

In setting up the apparatus the supports 21 and 33 are adjusted to the desired angle so that the angle between them will be equal to the angle of the conical portion 10 of a knob to be stamped and are then locked in adjustable position. The slide 18 may be adjusted at this time t insure proper registration of the die with the knob. The cross member 47 may be connected to the piston of motor 45 through a slot so that it can be adjusted to maintain the racks in proper vertical alignment with the slots 52 and the racks may be adjusted longitudinally of the slots to accommodate the adjusted positions of the gears. When adjusted, the rack 48 is locked in position relative to its slot 52 by tightening the corresponding nut 54 but the rack 49 is left unlocked to slide longitudinally of its slot 52 so that it may move with the slide 32 as it moves toward and away from the support 21. In this way, the apparatus can accommodate knobs or like articles having substantially any desired cone angle.

Air for operation is supplied from any desired source through a pipe 55 and an oil injector 55a which supplies oil to the air to lubricate the motors and bearings. The motor 45 is controlled by a control valve 56 which is electrically operated, as illustrated diagrammatically in Figure 7 and as described more fully hereinafter. As shown in Figure 2, exhaust air from the motor 45 flows back through the valve 56 and is conducted therefrom through a hose 57 to one end of the bearing block 34. This air may flow through the hollow bearing block around the shaft and may exhaust through a mufller 58 so that the shaft 35 and bearings 36 will not become overheated due to their proximity to the heating element 39 and will be lubricated. In this way, each time the motor 45 operates the exhaust air therefrom will circulate through the block 34 and keep the block and associated parts cool enough to prevent damage thereto and to maintain proper operation of the bearings.

The slide 32 may be moved along the guides 19 toward and away from the support 21 by a similar reversible air motor 59 which is secured to the table 15. The motor 59, as seen in Figure 7, is controlled by a solenoid operated valve 60 connected to the air source 55 to move the slide 32 toward the support 21 thereby to bring the conical die surface 44 into engagement with the conical surface of a knob on the support 26 for stamping the knob and to move the slide 32 away from the support 21 for ejection of a completed knob and mounting of a new knob to be stamped.

The knobs to be stamped are held on the supports 26 by a holder, as best seen in Figures 3 and 4, which is controlled by a similar reversible air motor 61, which has a piston rod 62 extending through a sleeve 63 fixedly mounted on the support and formed with a cam slot 64 therein extending axially adjacent to the motor and having an angularly curved portion remote from the motor. The pin 65 on the rod 62 fits slidably in the slot 64 so that as the piston rod 62 is moved axially the pin will cause it to shift axially and to turn laterally toward the end of its outward movement.

The rod 62 carries a holder comprising an arm 66 secured to the rod and carrying at its outer end a head element 67 shaped, as shown in Figure 5, to engage the outer end of a knob on the support 26 to hold the knob in place. When the rod 62 is shifted to the right, as shown in Figures 3 and 4, it will move the holder 67 axially away from the support 26 and will shift it laterally out of axial alignment with the support so that a knob may be placed on the support or may be ejected therefrom without interference. When the rod 62 is shifted to the left, as shown in Figure 4, the holder 67 will be swung into axial alignment with the support and will be moved toward the support to engage a knob on the support and hold it in place.

The ejector is operated by the reversible air motor 68 mounted on the support 21 and connected to the rod 31 which extends through the shaft 24. The motor 68 is controlled by a built-in control valve which is electrically operated in a manner similar to the valves 56 and 61 to the overall cycle of operations. The motor 68 is supplied with air fromthe source. 55, the air connections having been omitted in. Figure 7,- to avoid confusion.

A pigmented tape 69 isadapted to be fed between the die and knob during the stamping operation. As. shown in Figure 2, the tape is carried by a spool 71 supported on a bracket 72 adjustably carried by an extension of the bearing block 34 so that the tape will be properly positioned between the conical surfaces. of the die and the knob duringthe stamping operation. The tape passes downward through the opening 16 in the table and is adapted to be fed by a friction feeding mechanism, as shown in Figure 6. As illustrated in this figure, the mechanism comprises ashaft 73 carrying a drum 74 over which a cable 75 is wound. The upper end of the cable 75 may be connected to the cross member 47, as shown in Figure 2, and its. lower end after looping over the drum 74 may be connected to a spring or weight to maintain the cable tight and to pull it downward as the cross member 47 moves downward.

The shaft 73 rotatably supports a roller 76 which may be covered by rubber or similar friction material and which carries adjacent one end a ratchet 77. The roller freely rotatable on the shaft- 73 and. is adapted to be driven from the shaft by a friction disc 79 engageable with one end of the roller and which carries a pin 78 extending through an axially elongated slot in the shaft. A spring 81 in the shaft engages the pin 79 to urge the friction disc 78 into engagement with the roller 76 and may be adjusted by a screw 82 threaded into the end of the shaft. In this way, the roller 76 is friction driven so that it can never exert more than a predetermined ten- :sion on the tape and so that the shaft 73 can move independently of the roller.

The tape is pressed against the roller 76 by a back-up :roller 83 so that the tape will be gripped by the roller 76- at all times. Backward turning of the roller 76 which would create slack in the tape is prevented by a pawl 84 pressed into engagement with the ratchet 77 by a spring 85. With this constmction when the cross member 47 moves downward the roller 74 will be turned through the friction driving means in a direction to ad- Vance the tape and to insure that the tape will move with the knob and die. The friction driving means is adjusted so that the tape feed can never exert sufl'lcient tension on the tape to cause breakage thereof, but so that there will be sufiicient tension at all times to insure proper advancing of the tape. As the cross member 47- rises, thepawl 84 will engage the ratchet 77 to hold the roller 76.- against reverse movement and at this time the friction means will slip so that the shaft 73 may be driven in a reverse direction without driving the roller backwards.

The apparatus is controlled in a semiautomatic cycle by a control circuit, as illustrated diagrammatically in Figure 7. As shown in this figure, one side of a voltage source 86 is connected through a starting switch 87 and a pair of parallel switches 88 to the valve 60. The switches 87 and 88' may be positioned on the table, as shown in Figure 2, so that both hands; of the operator are required simultaneously toclose the switch 87 and one of the switches 88 thereby insuring that the operators hands are out of the way and he will not be damaged or injured by operation of the apparatus. The other side of the valve 60 is connected through a line 89 to the other side of the power source so that when the switches 87 and 88 are closed, the valve 60-will be shifted to a position to cause the motor 59 to move the slide 32 toward the support 21 to bring the die into engagement with the knob with the tape 69- therebetween. It will be understood that the switches 87 and 88 are only closed temporarily to shift valve 60 and are then released to reopen, the remainder of the cycle proceeding automatically as. described hereinafter.

When the slide 32 has been moved toward the support. 21 sufliciently to. bring; the die, into. engagement with the knob an operating projection 91 carried by thepistor'r rod of the motor 59 will engage and close a switch 92 which connects one side of the source 86 through a line 93. to the valve 56. The other side of the valve 56 is. connected directly to the other side of the source through a line 94. Thus after the die has been brought into engagement with the knob, the valve 56 willbe energized. to cause the motor 45' to shift the cross member 47 downward. At this time, the racks 48. and 49 will rotate the shafts 24 and 35 synchronously sothat the conical surface of the knob will be. stamped by the die without any slipping or smearing.

As the motor 45 moves the cross member 47 downward, a cam projection carried by the motor will first engage and close a switch- 95 which is connected in circuit with the valve 60 to reverse the valve. As shown, one side of the valve at the lower end thereof is directly connected to one side of the source through a line 96 and the other side of the valve is connected through the switch 95 to the other side of the source. Thus, when the switch 95 is closed the valve 60 will be reversed to cause the motor 59 to reverse to move the slide 32 away from the knob support. It will be noted that the motor 61 is connected in parallel with the motor 59 so that when the slide 32 is moved toward the knob support the knob holder will be operated to. engage and hold a knob on the support and when the slide is moved away from the knobsupport the knob holder will be moved out of the Way to the position shown in Figures 2 and 3.

As the motor 45 moves still further downward, preferably only a slight distance beyond the point at whichit closes the switch 95, a cam projection thereon willengage and close a switch 97. This switch controls a circuit through the valve 56 leading directly from one side of the source through a line 98 through the valve to the switch 97 which is connected to the opposite side of the line. When the switch 97 is closed, the valve 56 will be reversed to reverse motor 45 and raise the cross'member 47. Raising of the cross member 47 reverses the shafts 24 and 35 and returns both the die and the knob holder to their-initial positions.

When the slide 32 has. been completely returned to its initial position spaced from the knob support, the projection 91 thereon will engage and close a switch 99' which is connected directly between one side of the source and the valve for the motor 68. The opposite side of the valve for the motor 68 is connected to the other side of the source so that when the switch 9.9 is closed the motor 68 will be energized in a direction to move the ejector downward, as seen in Figure 5,. to eject a completed knob from the support. It will be noted that at the time the ejection occurs the support 32 is fully retracted from the knob support and the holder. 67 is moved axially and laterally away from the knob so that the completed knob can be ejected. Preferably the control for the motor 68 will cause the motor to operate to effect the ejection and then will de-energize the motor so that the spring- 29 can return the ejector and a fresh knob can be placed on the support. With this construction, it will be seen that the operation is semi-automatic so that when a knob is placed on the support and the switches 87 and 88 are closed the apparatus will pro ceed automatically through the complete cycle to finish stamping the knob and to eject the completed knob with the apparatus being left in condition to receive a new knob.

While one embodiment of the invention has been shown and described herein, it will be understood that it is illustrative only and not to be taken as. a definition of the scope of the invention, reference being had for this purpose to the appended claims.

What is claimed is:

1. Stamping apparatus for conical knobs and the like comprising a pair of shafts rotatably mounted in a common plane at; an acute angle toeach. other equal. to the full angle of the conical knob, means for mounting a conical knob to be stamped on one of the shafts, a conical-die on the other shaft having a cone angle the same as the cone angle of the knob and of substantially the same size as the knob, means mounting the shafts for bodily linear movement in said commone plane relatively toward and away from each other to bring the conical surface of the die into engagementwith the conical surface of the knob, and driving means connected to the shafts remote from the knob and die for simultaneously rotating the shafts in synchronism with each other.

2. Stamping apparatus for conical knobs and the like comprising a pair of shafts rotatably mounted in a common plane at an acute angle to each other equal to the full angle of the conical knob, means for mounting a knob to be stamped on one of the shafts, a conical die on the other shaft, means mounting the shafts for movement relatively toward and away from each other to bring the conical surface of the die into engagement with the conical surface of the knob, driving means for simultaneously rotating the shafts in synchronism with each other, control means operated by movement of the shafts relatively toward each other to energize the driving means, power means to move the shafts relatively toward and away from each other, and control means operated by the driving means after it has turned the knob and die through a predetermined angle to energize the power means to move the shafts relatively away from each other.

3. Stamping apparatus for conical knobs and the like comprising a pair of shafts rotatably mounted in a common plane at an acute angle to each other equal to the full angle of the conical knob, means for mounting a knob to be stamped on one of the shafts, a conical die on the other shaft, means mounting one of the shafts for bodily movement in said common plane toward and away from the other shaft, power means to move said one of the shafts, driving means for simultaneously rotating the shafts in synchronism with each other, a first manually operable control to energize the power means to move said one of the shafts toward the other shaft and to bring the conical surface of the die into engagement with the conical surface of the knob, a second control operated by the power means after a predetermined move ment thereof to energize the driving means, and control means operated by the driving means after predetermined movement thereof to reverse the power means to move said one shaft away from the other shaft and thereafter to reverse the driving means.

4. Stamping apparatus for conical knobs and the like comprising a pair of shafts rotatably mounted in a common plane at an acute angle to each other equal to the full angle of the conical knob, means for mounting a knob to be stamped on one of the shafts, a conical die on the other shaft, means mounting one of the shafts for bodily movement in said common plane toward and away from the other shaft, power means to move said one of the shafts, driving means for simultaneously rotating the shafts in synchronism with each other, a first manually operable control to energize the power means to move said one of the shafts toward the other shaft and to bring the conical surface of the die into engagement with the conical surface of the knob, a second control operated by the power means after a predetermined movement thereof to energize the driving means, control means operated by the driving means after predetermined movement thereof to reverse the power means to move said one shaft away from the other shaft and thereafter to reverse the driving means, an ejector to eject a finished knob from the shaft on which it is mounted, and a control operated by the power means upon movement thereof separating the shafts to operate the ejector.

Stamping apparatus for conical knobs and the like comprising a pair of shafts rotatably mounted in a common plane at an acute angle to each other equal to the full angle of the conical knob, means for mounting a knob to be stamped on one of the shafts, a conical die on the other shaft, means mounting the shafts for movement relatively toward and away from each other to bring the conical surface of the die into engagement with the conical surface of the knob, a spool supporting a ribbon for passage between the die and the knob, driving means for simultaneously rotating the shafts in synchronism with each other, feeding means for the ribbon, and friction means connecting the feeding means to the driving means to operate the feeding means to maintain a pre determined tension on the ribbon when the driving means is operating.

6. Stamping apparatus for conical knobs and the like comprising a pair of shafts rotatably mounted in a common plane at an acute angle to each other equal to the full angle of the conical knob, means for mounting a knob to be stamped on one of the shafts, a conical die on the other shaft, means mounting the shafts for movement relatively toward and away from each other to bring the conical surface of the die into engagement with the conical surface of the knob, a spool supporting a ribbon for passage between the die and the knob, reversible driving means for simultaneously rotating the shafts in one direction through a predetermined angle when they are together and rotating them in the reverse direction when they are separated, feeding means engaging the ribbon to urge it through the die and knob, a ratchet engaging the feeding means to prevent reverse rotation thereof, and friction drive means connecting the feeding means to the reversible drive means.

7. Stamping apparatus for conical knobs and the like comprising a pair of shafts rotatably, mounted in a common plane at an acute angle to each other, a support on the end of one of the shafts to receive a knob, a conical die on the end of the other shaft, means mounting the shafts for movement relatively toward and away from each other to move the conical surface of the die into and out of engagement with the conical surface of the knob, a holding device movable laterally into and out of alignment with said one of the shafts and axially 'toward and away from the support to hold a knob on the support or to release the knob, an ejector in the support to eject a completed knob axially therefrom, driving means for rotating the shafts, power means to move the shafts toward and away from each other and to operate the holding device and ejector and control means operable in a cycle to control the power means to move the shafts together and the holding device into engagement with a knob on the support, energize the driving means to rotate the shafts, move the shafts apart and the holding device away from the knob, and operate the ejector.

8. Stamping apparatus for conical knobs and the like comprising a pair of shafts rotatably mounted in a common plane at an acute angle to each other, a support on the end of one of the shafts to receive a knob, a conical die on the end of the other shaft, means mounting the shafts for movement relatively toward and away from each other to move the conical surface of the die into and out of engagement with the conical surface of the knob, a holding device movable axially toward and away from the support to hold a knob on the support, cam

means to move the holding device laterally out of alignment with the support when it moves away from the support, an ejector in the support to eject a completed knob therefrom, reversible motors to move the shafts relatively together and apart, to rotate the shafts, to move the holding means, and to operate the ejector, and control means to operate the motors in a timed cycle.

9. In a stamping apparatus for conical knobs and the like, a pair of shafts rotatably mounted in a common plane at an. angle to each other, a support on one of the shafts to hold a knob coaxially therewith, a conical die on the other shaft, driving gears on the shafts, racks perpendicular to said plane and meshing with the driving gears, a linearly movable reversible motor having a head parallel to said plane and movable toward and away from said plane, sliding connections between the racks and head for relative sliding parallel to said plane, and means mounting the shafts for relative movement toward and away from each other in said plane to move the conical surfaces of the die and a knob on the support into and out of engagement with each other.

10. In a stamping apparatus for conical knobs and the like, a pair of shafts rotatably mounted in a common plane at an angle to each other, a support on one of the shafts to hold a knob coaxially therewith, a conical die on the other shaft, driving gears on the shafts, racks perpendicular to said plane and meshing with the driving gears, a linearly movable reversible motor having a head parallel to said plane and movable toward and away from said plane, sliding connections between the racks and head for relative sliding parallel to said plane, means mounting the shafts for relative movement toward and away from each other in said plane to move the conical surfaces of the die and a knob on the support into and out of engagement with each other, a spool mounted above the shafts carrying a ribbon which extends downward between the conical surfaces of the die and knob, feeding means for the ribbon below the shafts, and one way drive means connecting the feeding means to the reversible motor.

11. In a stamping apparatus for conical knobs and the like, a pair of shafts rotatably mounted in a common plane at an angle to each other, a support on one of the shafts to hold a knob coaxially therewith, a conical die on the other shaft, driving gears on the shafts, racks perpendicular to said plane and meshing with the driving gears, a linearly movable reversible motor having a head parallel to said plane and movable toward and away from said plane, sliding connections between the racks and head for relative sliding parallel to said plane, slides on which the shafts are mounted and which are movable parallel to said plane relatively toward and away from 10 each other parallel to said sliding connections and adjustable perpendicular to said sliding connections, and means to turn the shafts on the slides about axes perpendicular to said plane to accommodate knobs having different cone angles.

12. In a stamping apparatus for conical knobs and the like, a pair of shafts in a common plane at an angle to each other, a hollow bearing block through which one of the shafts extends and in which it is journaled, a die carried by said one of the shafts, heating means for the die, an air operated motor connected to the shafts to turn them, and a connection from the exhaust of the motor to the bearing block to circulate exhaust air from the motor through the bearing block to cool it.

13. In a stamping apparatus for conical knobs and the like, a pair of shafts in a common plane at an angle to each other, a hollow bearing block through which one of the shafts extends and in which it is journaled, said one of the shafts terminating at one end beyond the bearing block in a series of spaced axially extending bores, heating elements supported in the bores and projecting beyond the end of the shaft, a die secured to the end of the shaft and formed with axially extending recesses into which the heating elements fit, a support on the end of the other shaft to support a knob to be stamped, an air operated motor connected to the shafts to turn them, and a connection from the motor to the bearing block to circulate exhaust air from the motor through the bearing block to cool it.

References Cited in the file of this patent UNITED STATES PATENTS 1,172,184 Waterman Feb. 15, 1916 1,331,790 Venge Feb. 24, 1920 1,360,723 Camp Nov. 30, 1920 1,800,350 Kirsch et al. Apr. 14, 1931 2,306,092 Throp Dec. 22, 1942 

